Hi jcbian,

This patch adds a driver for PIXCIR's I2C connected touchscreens.
Request the IRQ by doing request_threaded_irq() as v3.

Some MT comments below.

+static int pixcir_ts_poscheck(struct pixcir_i2c_ts_data *data)

Perhaps it is possible to find a more descriptive name?

+{
+	struct pixcir_i2c_ts_data *tsdata = data;
+
+	u8 touching, oldtouching;
+	u16 posx1, posy1, posx2, posy2;
+	u8 rdbuf[10], wrbuf[1];
+	int ret;
+
+	memset(wrbuf, 0, sizeof(wrbuf));
+	memset(rdbuf, 0, sizeof(rdbuf));
+
+	wrbuf[0] = 0;
+	ret = i2c_master_send(tsdata->client, wrbuf, 1);
+	if (ret != 1) {
+		dev_err(&tsdata->client->dev, "Unable to write to i2c touchscreen!\n");
+		goto out;
+	}

How about returning the error code here directly instead?

+
+	ret = i2c_master_recv(tsdata->client, rdbuf, sizeof(rdbuf));
+	if (ret != sizeof(rdbuf)) {
+		dev_err(&tsdata->client->dev, "Unable to read i2c page!\n");
+		goto out;
+	}

Ditto.

+
+	touching = rdbuf[0];
+	oldtouching = rdbuf[1];

Is oldtouching ever used?

+	posx1 = ((rdbuf[3] << 8) | rdbuf[2]);
+	posy1 = ((rdbuf[5] << 8) | rdbuf[4]);
+	posx2 = ((rdbuf[7] << 8) | rdbuf[6]);
+	posy2 = ((rdbuf[9] << 8) | rdbuf[8]);
+
+	input_report_key(tsdata->input, BTN_TOUCH, touching);
+
+	if (touching == 1) {
+		input_report_abs(tsdata->input, ABS_X, posx1);
+		input_report_abs(tsdata->input, ABS_Y, posy1);
+	}

No MT data for one finger?

+
+	if (touching == 2) {
+		input_report_abs(tsdata->input, ABS_MT_POSITION_X, posx1);
+		input_report_abs(tsdata->input, ABS_MT_POSITION_Y, posy1);
+		input_mt_sync(tsdata->input);
+
+		input_report_abs(tsdata->input, ABS_MT_POSITION_X, posx2);
+		input_report_abs(tsdata->input, ABS_MT_POSITION_Y, posy2);
+		input_mt_sync(tsdata->input);
+	} else
+		input_mt_sync(tsdata->input);

input_mt_sync() is always called, please simplify.

+	input_sync(tsdata->input);
+
+	return 0;
+
+out:
+	return -EINVAL;
+}
+

[...]

+static int pixcir_i2c_ts_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct pixcir_i2c_ts_data *tsdata;
+	struct input_dev *input;
+	const struct pixcir_i2c_ts_platform *pdata =
+					client->dev.platform_data;
+	int error;
+
+	if (!pdata) {
+		dev_err(&client->dev, "platform data not defined\n");
+		return -EINVAL;
+	}
+
+	tsdata = kzalloc(sizeof(*tsdata), GFP_KERNEL);
+	if (!tsdata) {
+		dev_err(&client->dev, "Failed to allocate driver data!\n");
+		error = -ENOMEM;
+		dev_set_drvdata(&client->dev, NULL);
+		return error;
+	}
+
+	dev_set_drvdata(&client->dev, tsdata);
+
+	input = input_allocate_device();
+	if (!input) {
+		dev_err(&client->dev, "Failed to allocate input device!\n");
+		error = -ENOMEM;
+		input_free_device(input);
+		kfree(tsdata);
+	}
+
+	init_waitqueue_head(&tsdata->wait);
+
+	input->name = client->name;
+	input->id.bustype = BUS_I2C;
+	input->dev.parent = &client->dev;
+
+	input->close = pixcir_ts_close;
+
+	input_set_drvdata(input, tsdata);
+
+	tsdata->client = client;
+	tsdata->input = input;
+	tsdata->chip = pdata;
+	tsdata->irq = client->irq;
+
+	set_bit(EV_SYN, input->evbit);
+	set_bit(EV_KEY, input->evbit);
+	set_bit(EV_ABS, input->evbit);
+	set_bit(BTN_TOUCH, input->keybit);
+	input_set_abs_params(input, ABS_X, 0, pdata->ts_x_max, 0, 0);
+	input_set_abs_params(input, ABS_Y, 0, pdata->ts_y_max, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_X, 0, pdata->ts_x_max, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, pdata->ts_y_max, 0, 0);

Is the device not capable of finger tracking? If not, it might be time
to turn finger tracking on in the input core. It is preferrable to use
protocol B these days.

+
+	if (input_register_device(input)) {
+		input_free_device(input);
+		kfree(tsdata);
+	}
+
+	if (request_threaded_irq(tsdata->irq, NULL, pixcir_ts_isr,
+			IRQF_TRIGGER_FALLING, client->name, tsdata)) {
+		dev_err(&client->dev, "Unable to request touchscreen IRQ.\n");
+		input_unregister_device(input);
+		input = NULL;
+	}
+
+	device_init_wakeup(&client->dev, 1);
+
+	return 0;
+}

Thanks,
Henrik